Water Supply Strategies
The 2011 Water Resources Plan anticipates adequate supplies to meet projected demand over the next fifty years under normal conditions. However, the Plan identifies water supply strategies to better prepare for growing demands and potentially severe surface water shortfalls. While Phoenix will take efforts to reduce water demand during severe shortages, the City also will be working towards making additional supplies available in the future. The main sources of new supplies will include recovering water that has been recharged into the aquifer, reclaimed water, new well capacity and additional supplies from the Central Arizona Project (CAP).
Arizona Water Banking Authority: "Shortage Insurance"
The Arizona Water Banking Authority (AWBA) has recharged more than 3-million acre-feet of Colorado River water for municipal and industrial CAP subcontractors. The water has been stored in numerous aquifer storage facilities and the credits for this water will be available for use by CAP when allocations are reduced. The means of recovering these credits and related policies are currently being considered by CAP, AWBA, and affected subcontractors have not yet been determined. Though deficit conditions are many years away, the planning coordination, funding and development of capital improvements to make the recovered water available will require substantial effort.
Caption plum: Groundwater Pump
Expanded Local Groundwater Reclaimed Water
Service Area Wells
Aside from additional surface water supplies, local groundwater is the most accessible supplemental supply. Through the City's Designation of Assured Water Supply, legal and physical access to more than 3.5 million acre-feet of groundwater in the Phoenix service area over a 100 year period, (an average of more than 35,000 acre-feet per year) has been demonstrated. The City has the current capability of producing 15,000-20,000 acre-feet per year, and typically withdraws between 6,000 and 9,000 AF per year. Opportunities exist to expand well capacity within the service area by rehabilitating older wells and developing new service area wells.
Non-Services Area Wells and Groundwater Exchanges
If developing additional services area wells is not practical or cost effective, wells outside of the Phoenix service area could be used to access both groundwater and stored water credits. Potential means for accomplishing this include:
- Storage and recovery of surface water supplies from an existing or future recharge facility accessible to the CAP or SRP canal systems.
- Developing an exchange agreement with one or more entities that have CAP allocations and substantial stand-by well capacity. Groundwater would be pumped by the other entity in place of its CAP supply, and Phoenix would take the CAP supply at its treatment plant.
- Develop an agreement to store and recover water within another water provider's service area, also through an exchange agreement.
CAP Allocated for State Lands in Phoenix
A 12,000 acre-foot portion of the municipal and industrial-priority CAP supplies allocated to the Arizona State Land Department is being held in reserve for State Trust lands in Phoenix north of Jomax Road. Phoenix's original CAP subcontract envisioned Jomax Road as the City's northern boundary. Based on a 1986 commitment from the State Land Department, this allocation will be transferred to Phoenix as State Trust lands in the area north of Jomax are developed.
White Mountain Apache Indian Lease
Phoenix has agreed to lease more than 3,000 AF of CAP water allocated to the White Mountain Apache community. The agreement was approved by Congress in December, 2010, and is expected to be implemented by 2015.
Underground Storage and Recovery of Unused Supplies
The successful storage by the Arizona Water Banking Authority of more than 3-million acre-feet of CAP water has significantly reduced the need for Phoenix to independently store water to compensate for future CAP deficits. However, it may still be practical for Phoenix to independently store water to prepare for simultaneous CAP and Salt and Verde Rivers deficits.
Reclaimed Water Use
As Phoenix water demand grows and existing water resources become more susceptible to drought-related shortages, reclaimed water (a relatively stable water source) will become an increasingly important component in Phoenix's water supply portfolio. A key benefit of reclaimed water is that the available volume increases as overall potable use increases. In addition, as urbanization occurs, reclaimed water currently used for agriculture will become available for other uses.
Funding for new supplies is made available through Water Resource Acquisition Fees which are assessed to new development. This fee structure helps ensure that "growth pays for itself." More information on how Phoenix plans to develop the City's water supply portfolio can be found in the 2011 Water Resources Plan.
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